package summary;

/**
 * @Author: 海琳琦
 * @Date: 2022/3/11 9:45
 * https://leetcode-cn.com/problems/unique-paths-ii/
 */
public class Title63 {

    /**
     * dp[i][j]表示到达i、j位置经过路径的个数
     * 递推公式 dp[i][j] = dp[i-1][j] + dp[i][j-1]
     * 初始化 if(obstacleGrid[0][j] == 0) dp[0][j] = 1
     * @param obstacleGrid
     * @return
     */
    public int uniquePathsWithObstacles(int[][] obstacleGrid) {
        int m = obstacleGrid.length;
        int n = obstacleGrid[0].length;
        int[][] dp = new int[m][n];
        //初始化
        for (int i = 0; i < m; i++) {
            if (obstacleGrid[i][0] == 1) {
                break;
            }
            dp[i][0] = 1;
        }
        for (int j = 0; j < n; j++) {
            if (obstacleGrid[0][j] == 1) {
                break;
            }
            dp[0][j] = 1;
        }
        for (int i = 1; i < m; i++) {
            for (int j = 1; j < n; j++) {
                if (obstacleGrid[i][j] != 1) {
                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
                }
            }
        }
        return dp[m - 1][n - 1];
    }

    public static void main(String[] args) {

    }
}
